Question

The actual distance between two places in a topographical map with map distance 15 cm is 75 km. The scale of the map is

• A. 1: 100000
• B. 1: 250000
• C. 1:50000
• D. 1:25000

Answer 1

Answer:

C. 1:50000

Understanding Map Scale: The Representative Fraction

• A map scale represents the ratio between a distance on a map and the corresponding distance on the actual ground. It is fundamental for interpreting distances, areas, and features depicted on maps.

• There are three primary ways to express map scales:

  • Verbal Scale: Expressed in words, e.g., '1 cm to 5 km'.

  • Graphical Scale (Bar Scale): A line marked with distances on the ground, allowing direct measurement.

  • Representative Fraction (RF): A ratio or fraction (e.g., 1:50,000 or 1/50,000) where the numerator (usually 1) represents a unit of distance on the map, and the denominator represents the same unit of distance on the ground.

• The Representative Fraction (RF) is a dimensionless ratio, meaning the units on both sides of the colon (or in the numerator and denominator) must be the same (e.g., cm to cm, inches to inches). This makes it universally applicable regardless of the measurement system used.